This invention relates generally to apparatus, methods and materials for absorbing magnetic radiation such as that produced by video display units and more specifically to apparatus that may be mounted on video display units of different shapes and sizes to absorb such radiation.
There has been a growing concern about the health hazards related to prolonged exposure to ELF (extremely low frequency) magnetic radiation produced by video display units such as computer terminals, monitors, television sets and the like. See, for example, the article entitled "The Risk of Miscarriage and Birth Defects Among Women Who Use Visual Display Terminals During Pregnancy" in the Jun., 1988 issue of the American Journal of Industrial Medicine; the book entitled "Currents of Death" authored by Paul Brodeur and published in 1989 by Simon & Schuster; the article entitled "EPA Suspects ELF Fields Can Cause Cancer" in the Jun. 30, 1990 issue of Science News; the article entitled "The Magnetic Field Menace" in the Jul., 1990 issue of MacWorld; and the article entitled "Danger From a Glowing Screen" in the Jul. 18, 1990 issue of Time Magazine. Since the use of video display units has become so widespread and so continuous from day to day both in the workplace and the home, the health hazards related to prolonged exposure to ELF magnetic radiation must be taken seriously. Thus, anything that can be done now to reduce those health hazards both in connection with the video display units currently in use and in connection with the manufacture of new video display units is extremely important.
Accordingly, the purpose of this invention is to provide methods and means for reducing the operators' and others' exposure to ELF magnetic radiation such as that produced by video display units. This purpose is achieved in accordance with one of the illustrated preferred embodiments of this invention by providing a kit including a plurality of elongated flexible elements or strips of magnetic material and both hook- and loop-type tape for removably mounting the strips of magnetic material on a video display unit around the back from one side to the other and over the top from one side to the other in orthogonally intersecting planes. Each strip of magnetic material has a grain orientation parallel to its longitudinal axis and is formed from ferromagnetic material in the range from M3 to M7. The strips of magnetic material absorb magnetic radiation produced by the video display unit, thereby reducing the user's exposure to ELF magnetic radiation without interfering with the viewing of the display of the video display unit and without hampering the air flow for cooling the video display unit. By selectively attaching the hook- and loop-type tape to the strips of magnetic material and to the video display unit itself, the strips of magnetic material may be easily mounted and positioned on the video display unit and may be just as easily removed and subsequently remounted as might be necessary for packing and transporting the video display unit or for any other purpose.
In accordance with another of the illustrated preferred embodiments of this invention, there is provided a multiple-layer magnetic shielding material comprising first and second layers of grain-oriented ferromagnetic material in the range from M3 to M7. These layers are bonded or otherwise secured together with the grain orientation of the first layer orthogonal to the grain orientation of the second layer. This grain-oriented multiple-layer magnetic shielding material is much less costly than conventional non-grain-oriented magnetic shielding materials, such as Mu-metal, and is of comparable efficiency. The strips of magnetic material to be mounted on the video display unit, as described above, may therefore also be formed from this grain-oriented multiple-layer magnetic shielding material without unduly increasing the cost of the strips of magnetic material and, hence, of the kit for absorbing magnetic radiation produced by the video display unit.